chore: Port FreeSewing.dev to docusaurus

The replaces the NextJS site powering FreeSewing.dev with a Docusaurus
setup. It's part of my efforts to simplify FreeSewing's setup so we can
focus on our core value proposition.

sites/dev/docs/reference/api/path/roughlength/readme.mdx

@@ -0,0 +1,50 @@
+---
+title: Path.roughLength()
+---
+
+The `Path.roughLength()` method returns a (very) rough estimate of the path's length.
+
+## Signature
+
+```js
+Number path.roughLength()
+```
+
+## Example
+
+<Example caption="Example of the Path.attr() method">
+```js
+({ Point, points, Path, paths, macro, units, part }) => {
+
+  points.B = new Point(10, 30)
+  points.BCp2 = new Point(40, 20)
+  points.C = new Point(120, 30)
+  points.CCp1 = new Point(50, -30)
+
+  paths.example = new Path()
+    .move(points.B)
+    .curve(points.BCp2, points.CCp1, points.C)
+
+  macro("pd", {
+    path: paths.example,
+    d: -10,
+    text: `Path.roughLength() = ${units(paths.example.roughLength())}`
+  })
+  macro("pd", {
+    path: paths.example,
+    d: 10,
+    text: `Path.length() = ${units(paths.example.length())}`
+  })
+
+
+  return part
+}
+```
+</Example>
+
+## Notes
+
+The `Path.roughLength()` is not intended to give an estimate that is accurate, but rather differentiates between paths that are a few millimeter long, or meters long.
+
+It calculates the length without *walking the (cubic) Bézier curve* making it very fast and very inaccurate (for curves).
+It is typically used to determine how much precision to apply when walking a curve.